February 14, 2008

Meat-Eating Dinosaur Fossils Discovered In Africa

Paleontologists have discovered fossils in Africa's Sahara Desert of two new meat-eating dinosaurs that walked the earth 110 million years ago during the Cretaceous Period.  

The dinosaurs were discovered in 2000 during an expedition led by University of Chicago paleontologist Paul Sereno.  Sereno and co-author Stephen Brusatte of the University of Bristol reported the discovery in the journal Acta Palaeontologica Polonica.

In their report, they said the fossils provide a glimpse of an earlier stage in the evolution of the dinosaurs of Gondwana, the landmass in the Southern Hemisphere that separated to form South America, Africa, Antarctica, and Australia.

"T-rex has become such a fixture of Cretaceous lore, most people don't realize that no tyrannosaur ever set foot on a southern continent," said Sereno.

Instead, particularly distinctive meat-eaters arose, some of which bore no resemblance to the T-rex beyond their appetites for fresh meat.

The two dinosaurs, similar in size at about 25ft. in length and both insatiable meat-eaters, were named Kryptops palaios and Eocarcharia dinops.  

Kryptops Palaios, which means "old hidden face," was so named for its short snout and the horny covering that nearly covers all of its face. "A fast, two-legged hyena gnawing and pulling apart a carcass is how we might best imagine Kryptops' dining habits," said Brusatte.  "Like later members of its group (called abelisaurids) in South America and India, Kryptops had short, armored jaws with small teeth that would have been better at gobbling guts and gnawing on carcasses than snapping at live prey," he said.

Eocarcharia dinops, meaning fierce-eyed dawn shark, was so named for its blade-shaped teeth and prominent bony eyebrow. Unlike Kryptops, its teeth were designed for disabling live prey and severing body parts. Eocarcharia and kin (called carcharodontosaurids) gave rise to the largest predators on southern continents, matching or exceeding Tyrannosaurus in size.  Eocarcharia's brow was swollen into a massive band of bone, giving it a intimidating stare.

"Brow-beating may not be far from the truth," said Sereno. He and Brusatte suggest in their report that the strong bony brow in Eocarcharia may have been used as a battering ram against rivals for mating rights.

The fossil area,  in present-day Niger, was home to a panoply of peculiar species. The hyena-like Kryptops, the shark-toothed Eocarcharia and the fish-eating, sail-backed Suchomimus ("crocodile mimic") are meat-eaters characterizing the Cretaceous Period in Africa and possibly other southern landmasses.

They preyed upon the ground-grubbing, long-necked plant-eater Nigersaurus and lived alongside the enormous extinct crocodilian nicknamed "SuperCroc" (Sarcosuchus).  At that time, the African continent was part of Gondwana and just beginning to free itself of its land connection to South America.

The National Geographic Society, the Packard Foundation, the Pritzker Foundation and the University of Chicago funded the research.


The paper appears this month in the scientific journal Acta Palaeontologica Polonica. The full report can be viewed at http://www.app.pan.pl/acta53/app53-015.pdf.

Additional information on the new dinosaurs, their contemporary species and Cretaceous habitat, and the expedition on which the fossils were discovered is available at http://www.projectexploration.org.